Kiribanda, yes you can model the soil as a 2 layer model, it also has options to accept test results, such as the weener method.
umrpwr, I have sent Sakis a few questions, he has responded so far, I was just hoping to find some additional resources, such as a user group or similar, I am not sure such a thing exists though. If you don't mind answering, I have a simple model that I am trying to obtain a GPR on, basically it consists of a utility power source, 44/4.16 kv transformer, and grounding grid. I have a node on either side of the transformer and have connected the ground grid on the primary side. Now the odd thing is my results, the GPR does not seem to change no matter how I vary the grounding grid, my step and touch equipotential plots are in the pV range as well, this seems odd to me but I cannot figure out why.